Circular knitting machine of the superimposed needle cylinder type



Jan. 3, 1961 CIRCULAR KNITTING NEEDL Filed Jan. 26, 1959 3 Sheets-Sheet 1 lNl/EN TOR ///v/? 5/.0/VEY BOKOHT,

A TTORNE Y5 CIRCULAR KNITTING MACHINE OF THE SUPERIMPOSED NEEDLE CYLINDER TYPE Jan. 3, 1961 s, BURDETT 2,966,784

Filed Jan. 26, 1959 3 Sheets-Sheet 2 M601 at, ATTORNEY5 Jan. 3, 1961 s, BURDETT 2,966,784

CIRCULAR KNITTING MACHINE OF THE SUPERIMPOSED NEEDLE CYLINDER TYPE Filed Jan. 26, 1959 3 Sheets-Sheet 3 BY 5272, M

I ATTORNEXS CIRCULAR KNITTING MACHINE OF THE SUPER- IMPOSED NEEDLE CYLINDER TYPE England, assignor to Henry Sidney Burdett, Knighton,

England, a British G. Stibbe & Co. Limited, Leicester, company This invention relates to circular knitting machines of the superimposed needle cylinder type, that is to say machines of the type comprising, in combination, a bottom or plain needle cylinder, an axially opposed top or rib needle cylinder, a single set of double-ended latch needles for operation in said cylinders, and a set of sliders in each of the cylinders for actuating the needles and also for transferring the same from one cylinder to the other, and vice versa, in the production of various rib, purl and links-links fabrics and effects.

In a knitting machine of this type, the operative end of each slider is, as well known to those acquainted with such machines, provided at the back with a needle-pulling clutch adapted for engagement over and to act upon the free end of the relevant hook of the corresponding double-ended latch needle for the purpose of retracting the latter as required. Immediately adoining the needlepulling clutch of each slider the latter has therein a recess the transverse edge or side of which opposing the slider clutch is adapted to act on the outside of the engaged needle hook for the purpose of pushing and advancing the needle. The leading portion of each needleactuating slider in advance of its hook functions as a latch guard.

Whenever a needle is to be transferred from either cylinder to the other, the transferring slider at the time connected with the said needle is first advanced to a transfer position at which the needle is interrengaged with a previously empty receiving slider in the opposite cylinder and the said transferring slider is tilted or rocked outwardly from the cylinder from which the transfer is to take place suchwise as to release the needle. The outward tilting or rocking of a transferring slider simply displaces the slider clutch clear of the previously engaged hook of the corresponding needle so enabling this needle to be freely retracted into the opposed cylinder when once the hook at the opposite end of the needle has been grasped by the receiving slider in the last mentioned cylinder.

A conventional way of tilting or rocking needle-actuating sliders outwardly from a cylinder and so releasing them from needles in that cylinder is to act on the rear edges of the aforementioned leading sliders by means of a dividing cam. It has, however, previously been proposed-with the aim of obviating the necessity for dividing cams at a location between the axially opposed cylindersto recms the backs of the trail portions of the sliders to permit outward rocking of the latter, and to provide a slider-rocking cam arranged to engage the tail portions of such of the sliders as are moved to transfer position.

Now during a needle transferring action in a superimposed needle cylinder knitting machine of the type referred to, the latch at the end of the needle which is to be received by an empty receiving slider must be open. In the ordinary way, when yarn is feeding satisfactorily to the needle, this yarn can be relied on to openthe latch concerned. But in the event of the yarn breaking,

States Patent portions of the that the magnetic latch ice running out or otherwise failing so that no yarn is, in fact being fed to the needle, then an old loop on the needle, drawn at a previous course, will close the latch which latter, because of the absence of new yarn would then remain closed, unless some special provision were made for opening it again.

In such circumstances it is essential that satisfactory latch opening means shall be provided for opening closed latches of needles to be transferred. A mechanical latch opener is not satisfactory for this purpose because it tends to interfere with those needles not taking part in a transfer. Moreover, a mechanical latch opener is required to be inserted between the hooks and the latches of appropriate needles; as a consequence, any maladjustment of such an opener would tend to bend latches or even pull needles out of their tricks or grooves. A single damaged needle could, in fact, so upset a mechanical latch opener as to cause damage to the remainder of the needles. 1

The object of the present invention, therefore, is to provide simple and efficient means for ensuring that the latches associated with needle hooks to be grasped by receiving needles are open.

According to this invention there is provided in a superimposed cylinder machine, at a location immediately in advance of a region of transfer, a magnetic latch opener disposed at the fronts of the needles and adapted to at least partially open the latches of appropriate needles by magnetic attraction, for the purpose specified.

As will be appreciated, he magnetic latch opener is so designed and positioned as to be adapted to at least partially open relevant latches just before needles to be transferred enter the region of transfer and are momentarily hooked on to both transferring and receiving sliders preparatory to being released from the transferring sliders.

The magnetic latch opener, in fact, opens the relevant latches at least sutticiently far as to ensure that the leading portions of the receiving sliders, as they pass over the needle hooks to be grasped by the said sliders, fully open the said latches should that prove to be necessary.

In order that the invention may be more clearly understood and readily carried into practical effect, a specific example thereof as applied to a circular hose or half hose knitting machine will now be described with reference to the accompanying drawings, wherein,

Figure 1 is a fragmentary vertical sectional view of so much of the knitting head of such a machine taken on the lines 1-1 of Figure 2, as is necessary to illustrate the application thereto of a magnetic latch opener for the purpose in view,

Figure 2 is a developed layout, as viewed from the interior of the machine, illustrating the transfer sections and adjoining portions of the knitting sections of the cam systems of the said machine,

Figure 3 is a detail perspective view of a few of the needles of the machine, showing the latches of plain needles in the course of being at least partially opened by the magnetic latch opener,

Figure 4 is a detail plan view corresponding to Figure 3, and

Figure 5 is a further detail view illustrating the fact opener is capable of influencing the latches both of needles being transferred up as well as those of needles being transferred down.

Referring to Figure 1 it will be seen that the hose or half hose machine illustrated comprises a bottom or plain needle cylinder 1, and a superimposed top or rib needle cylinder 2. For operation in these cylinders is provided a single set of double-ended latch needles such as 3. That is to say, each needle is, in accordance with conventional practice, provided at each of its opposite ends with a hook 3a and an associated pivoted latch 3b. Also in the cylinders l and 2 are provided sets of bottom and top needle-actuating sliders such as 4 and 5 respectively, such sliders being employed in the usual way for transferring needles 3 from one cylinder to the other, according to knitting requirements. The customary hook-like needle-pulling clutch of each slider is indicated at 6. Each slider also has formed therein, adjacent to its clutch 6, a recess 7 of known form having a transverse edge 8 for action upon an engaged needle hook 3a when advancing the needle. The leading portion 9 of each of the bottom and top sliders functions as a needle latch guard.

The bottom and top cam boxes of the machine are indicated respectively at 10 and 11 in Figure 1. In the specific example illustrated, the cam boxes are stationary and the needle cylinders revolve therein, although the reverse could be the case.

Turning now to Figure 2 it will be seen that the forward stitch cam in the bottom cam box 10 is represented at 12, and that the numeral 13 is employed to designate the 'rib stitch cam in the top cam box 11. The conventional transfer cam in the bottom cam box for acting in the ordinary way on the transfer butts 4a of bottom sliders 4 is indicated at 14. 15 is a reverse welt cam of the bolt type which is movable into and out of operation at required times. Plain needles in the bottom cylinder 1 coupled with bottom sliders 4 which are elevated by the transfer cam 14 are accordingly raised to transfer height at which they are taken by relevant receiving needles in the top cylinder 2. At 16 is represented the conventional dividing cam for cooperation with the leading portions 9 of bottom sliders 4 raised for transfer as just mentioned for the purpose of tilting such sliders outwardly from the bottom cylinder 1 and so releasing them from the corresponding needles in the course of transference of the latter from the bottom cylinder into the top cylinder. The reference numeral 17 indicates a so-called half lift cam. In the possible case where both the reverse welt cam 15 and the half-lift cam 17 are in their operative positions together, these cams, by action upon the knitting butts 4b of the bottom sliders 4, will raise the latter to such a height that their transfer butts 4a are landed on to the transfer cam 14 with the result that corresponding needles in the bottom cylinder will in these particular circumstances also be fully advanced to transfer height for transference into the top cylinder.

A welt cam 18 is provided in the top camhox, and the transfer cam in this box is indicated at 19. Thus, where the transfer butts 5a of top sliders 5 are acted upon by the cam 19, these sliders, with rib needles coupled thereto, will be advanced so that opposite bottom sliders 4 can receive the said needles and transfer the same from the top cylinder to the bottom cylinder. During a downward transfer of needles, a further dividing cam 20 co-operates with the leading portions 9 of the relevant top sliders 5 to tilt the latter outwardly from the top cylinder and so effect their release from the needles to be received by the opposite bottom sliders.

Now in accordance with the characteristic feature 'of the present invention, there is provided, immediately in advance of the bottom and top transfer cams 14 and 19, a magnetic latch opener in the form of magnet 21 arranged on the outside of the needle circle and disposed at the fronts of the needles. As will be seen in Figure 2, the two attractive poles 21a and 21b of the magnet 21 extend longitudinally and horizontally at opposite sides of a median line extending through the two dividing cams 16 and 20. Thus, and as shown in Figure 5, the heightwise disposition of the lower pole 21a is such as to enable this pole to contact, attract and pull outwardly towards their open positions the pivoted latches 3b of needles 3 in'the course of being raised for transference from the bottom cylinder 1 into the top 5 cylinder 2. In a similar way, the disposition of the upper pole 21b is such as to enable the latter to similarly contact, attract and at least partially open the latches of needles in the course of being lowered (not advanced) for transference from the top cylinder to the bottom cylinder.

Preferably, the magnetic latch opener is in the form of an electro-magnet adapted-to generate an alternating magnetic field in advance of the transfer cams. Thus, in the specific example illustrated, the electro-magnet 21 comprises a metal core of the cross-section shown and the outer ends of the two limbs of which constitute the superimposed poles 21a and 21b separated by an interposed spacer 22 of any suitable insulating material. The appropriate portion of this core is surrounded by turns of wire 23 through which is arranged to be passed alternating current derived, for the purpose of safety, from the output of a suitable step-down transformer (not shown). An alternating current not exceeding twentyfour volts is suitable to generate the required magnetic field. Although a soft iron core, or a laminated silicon steel core may be adopted with some degree of success, it is preferred to employ a laminated core of a nickel based metal which, although adapted to be readily highly magnetised to produce a strong field, nevertheless has little or no residual magnetism whenever the flow of current through the turns of wire is stopped.

In the specific arrangement illustrated in Figures 3 and 4, the electro-magnet 21 is so disposed that its leading end is sufiiciently close to the fronts of the needles 3 as actually to contact closed latches 3b thereof requiring to be opened preparatory to a transfer of such needles. The magnet is, however, set tangentially with respect to the needle circle (see Figure 4) suchwise as to provide, between the magnet and the needles, a space S of gradually increasing width to permit of the latches 3b contacted by either of the poles 21a or 21b and influenced by the magnetic field to swing outwardly towards their open positions. In the illustrated example, moreover, at the same time that latches 3b are being at least partially opened under the influence of the electro-magnet 21, the relevant needles 3 are in the course of being advanced, to clear, by means of either the cam 15 or the cam 18, as the case may be.

As will be appreciated from a consideration of Figure 5, the magnetic field exercises an influence over the needle latches 312 until they have been turned outwardly away from the hooks 3a into approximately a horizontal status. But whether or not such latches, as they pass out of the magnetic field, fall into their fully open positions, or even tend (in the case of rib needles being advanced from the top cylinder) to fall again towards their closed positions, the fact that the latches have been at least partially opened'in the critical-region immediately in advance of the transfer cams is sufiicient for the purpose of the present invention since even such partial opening of latches ensures that the leading portions 9 of receiving sliders can properly be entered between the'hooks and the latches of those needles with which they are-to become coupled during a transfer.

In order to prevent latches'which may happen to be already partially open from crashing into and being bent or broken by the electro-magnet 21 as the relevant needles travel towards the transfer station, the said magnet is immediately preceded by two latch-guarding earns -24 and 25 which are so formed and arranged as to ensure closure of the latches of all needles retracted to knocking-over position by either the plain stitch cam 12, or the rib stitch cam 13, as the case may be. That is to say, the latchguarding cam 24 relates to the bottom cam system acts on the undersides of any open or partly open latches of plain needles in the bottom cylinder and turns these latches up and closes the same as the knitting butts 4bofthe corresponding bottom sliders 4 ride down the stitch cam 12. Similarly, the latch-guarding cam 25 associated with the top cam'syste'm acts on any open orpartly open latches of rib needles in the top cylinder and closes these latches as the knitting butts b of the top sliders ride down the rib stitch cam 13. In short, these latch-guarding cams position the latches in favourable positions to be influenced by the magnetic field without first being damaged or broken.

The magnetic latch opener may conveniently be carried by a bracket or other support attached to one of the two cam boxes of the machine. Thus, in the illustrated example, the electro-magnet 21 is carried by a bracket 26 attached to the bottom cam box (see Figures 1 and 3).

Although the illustrated example of the invention has been described as applied to a hose or half hose machine, the invention is also advantageously applicable to larger diameter body machines, especially multi-feed body machines having a plurality of needle transfer stations each preceded by a magnetic latch opener.

As far as a small diameter hose or half hose machine is concerned, a location immediately preceding a needle transfer station can in certain instances be very favourable for the presence of a magnetic field because in some such machines there is little or no ferrous metal at the said location. Thus, the exposed heads of needles advanced for transfer are clear of the steel needle cylinder from which they are so advanced, and when relevant latches are in the course of passing through the magnetic field the corresponding needle heads are backed, in these particular machines, by a brass sinker ring and a brass verge ring.

It would be possible for brass components to be employed at the corresponding regions of a body machine with the same advantage.

Moreover, the invention is not confined to the use of electro-magnetic latch openers since in certain cases permanent bar magnets may be adopted for the purpose in view.

I claim:

1. In a circular knitting machine, in combination, a bottom needle cylinder, a superimposed top needle cylinder, a set of double-ended latch needles operating in said cylinders, sliders in the bottom and top cylinders for actuating needles and transferring same from one cylinder to the other, according to knitting requirements, cam boxes surrounding the needle cylinders, transfer cams which are provided in these boxes at a needle transfer region for advancing the sliders and hence also needles in either cylinder to transfer level at which the said needles can be grasped by receiving sliders in the opposite cylinder, and, at a position immediately in advance of the needle transfer region a magnetic latch opener which is disposed at the fronts of the needles, and is adapted, by magnetic attraction, to at least partially open the latches of needles to be transferred from one cylinder to the other.

2. A combination according to claim 1, wherein the magnetic latch opener is in the form of an electro-magnet.

3. A combination according to claim 2, wherein the metal core of the electro-magnet is so formed as to present two superimposed and longitudinally extending poles separated by an interposed spacer of insulating material, the lower pole being disposed to contact, attract and pull outwardly latches of needles to be transferred up from the bottom cylinder into the top cylinder, and the upper pole being disposed similarly to contact and pull outwardly latches of needles to be transfered down from the top cylinder into the bottom cylinder.

4. A combination according to claim 2, wherein there is arranged to be passed through turns of wire surrounding a metal core of the electro-magnet alternating current of a comparatively low voltage.

5. A combination according to claim 2, wherein the core of the electro-magnet consists of laminations of a metal which is highly magnetizable and yet has little or no tendency to retain magnetism when the electric current is switched olf.

6. In a circular knitting machine, in combination, a bottom needle cylinder, a superimposed top needle cylinder, a set of double-ended latch needles operating in said cylinders, sliders in the bottom and top cylinders for actuating needles and transferring same from one cylinder to the other, according to knitting requirements, cam boxes surrounding the needle cylinders, transfer cams which are provided in these boxes at a needle transfer region for advancing the sliders and hence also needles in either cylinder to transfer level at which the said needles can be grasped by receiving sliders in the opposite cylinder, horizontal dividing cams in the cam boxes for action on the rear edges of leading portions of the bottom and top sliders for the purpose of tilting such sliders outwardly and releasing them from appropriate needles during a needle transfer operation, and, at a location immediately in advance of the needle transfer region, an electro-magnet constituting a magnetic latch opener which is disposed at the fronts of the needles and is adapted, by magnetic attraction, to at least partially open the latches of needles to be transferred, the metal core of the electromagnet being so formed as to present two superimposed and longitudinally extending poles separated by an interposed spacer of insulating material, the lower pole being disposed to contact, attract and pull outwardly latches of needles to be transferred up from the bottom cylinder into the top cylinder, and the upper pole being disposed similarly to contact and pull outwardly latches of needles to be transferred down from the top cylinder into the bottom cylinder, these superimposed poles of the electro-magnet being located at respectively opposite sides of a median line extending through the aforesaid horizontal dividing cams.

7. In a circular knitting machine, in combination, a bottom needle cylinder, a superimposed top needle cylinder, a set of double-ended latch needles operating in said cylinders, sliders in the bottom and top cylinders for actuating needles and transferring same from one cylinder to the other, according to knitting requirements, carn boxes surrounding the needle cylinders, transfer cams which are provided in these boxes at a needle transfer region for advancing the sliders and hence also needles in either cylinder to transfer level at which the said needles can be grasped by receiving sliders in the opposite cylinder, and, at a location immediately in advance of the needle transfer region, an electro-magnet constituting a magnetic latch opener which is disposed at the fronts of the needles and is adapted, by magnetic attraction, to at least partially open the latches of needles to be transferred, the metal core of the electromagnet being so formed as to present two superimposed and longitudinally extending poles separated by an interposed spacer of insulating material, the lower pole being disposed to contact, attract and pull outwardly latches of needles to be transferred up from the bottom cylinder into the top cylinder, and the upper pole being disposed similarly to contact and pull outwardly latches of needles to be transferred down from the top cylinder into the bottom cylinder, these superimposed poles of the electromagnet being set close to the fronts of the relevant needles and the magnet being tangentially disposed with respect to the needle circle suchwise as to provide, between the magnet and the needles, a space of increasing width to permit of outward turning movement of latches contacted by either of the poles.

8. In a circular knitting machine, in combination, a bottom needle cylinder, a superimposed top needle cylinder, a set of double-ended latch needles operating in said cylinders, sliders in the bottom and top cylinders for actuating needles and transferring same from one cylinder to the other, according to knitting requirements, cam boxes surrounding the needle cylinders, stitch cams in the cam boxes for retracting needles, through the medium of sliders, to knocking-over position, transfer cams which are provided in the cam boxes at a needle transfer region for advancing the sliders and hence also corresponding needles in'either cylinder to transfer level at which the said needles can be grasped by receiving sliders in the opposite cylinder, a magnetic latch opener disposed at the fronts of the needles at a location immediately in advance of the needle transfer region, the said latch opener being adapted, by magnetic attraction, to at leastpartially open the latches of needles to be transferred, and bottom and top latch guarding cams which precede the magnetic latch opener and are so formed for action on needle latches as to ensure closure of the latches of all needles retracted to knocking-over position by the stitch cams.

9. In a circular knitting machine, in combination, a bottom needle cylinder, a superimposed top needle cylinder, a set of double-ended latch needles operating in said cylinders, sliders in the bottom and topcylinders for actuating needles and transferring same from one cylinder to the other, according to knitting requirements, cam boxes surrounding the needle cylinders, transfer cams which are provided in these boxes at a needle transfer region for advancing the sliders and hence also needles in either cylinder to transfer level at which the said needles can be grasped by receiving sliders in the opposite cylinder, a magnetic latch opener disposed at the fronts of the needles at a location immediately in advance of the needle transfer region, the said latch opener being adapted, by magnetic attraction, to at least partially open the latches of needles to be transferred from one cylinder to the other, and a bracket which carries the magnetic latch opener and is attached to one of the two cam boxes of the machine.

10. In a circular knitting machine, in combination, a bottom needle cylinder, a superimposed top needle cylinder, a set of double-ended latch needles operating in said cylinders, sliders in the bottom and top cylinders for actuating needles and transferring same from one cylinder to the other, according to knitting requirements, cam

boxes surrounding the needle cylinders, transfer cams which are provided in these boxes at a needle transfer region for advancing the sliders and hence also needles in either cylinder to transfer level at which the said needles can be grasped by receiving sliders in the opposite cylinders, stitch cams in the cam boxes which last mentioned cams precede the transfer cams and retract needles through the medium of the sliders, to knocking-over position, a magnetic latch opener disposed at the fronts of the needles at a location immediately in advance of the needle transfer region, the said latch opener being adapted, by magnetic attraction, to at least partially open the latches of needles to be transferred, the metal core of the electro-magnet being so formed as to present two superimposed and longitudinally extending poles separated by an interposed spacer of insulating material, the lower pole being disposed to contact, attract and pull outwardly latches of needles to be transferred up from the bottom cylinder into the top cylinder, and the upper pole being disposed similarly to contact and pull outwardly latches of needles to be transferred down from the top cylinder into the bottom cylinder, and bottom and top latch guarding cams which precede the magnetic latch opener and are so formed for action on needle latches as to ensure closure of the latches of all needles retracted to knocking-over position by the stitch cams.

References Cited in the file of this patent UNITED STATES PATENTS 1,564,379 Stephens Dec. 8, 1925 2,406,579 Bassist Aug. 27, 1946 2,658,366 Shelmire Nov. 10, 1958 FOREIGN PATENTS 506,837 Great Britain June 6, 1939 

